It is well known that genetic markers can be obtained from DNA and used for a variety of purposes. For example, in the field of agriculture, the DNA that is taken from plant material will yield genetic markers that can be used in marker assisted breeding. In this process, DNA sequences are used to follow desirable agronomic traits in the process of plant breeding.
For marker assisted breeding, seeds of plants with a desired trait are planted either in a greenhouse, in a field or in a hydroponic system. Plant tissue (for example, leaf) is then harvested from the plants for preparation of DNA once sufficient tissue can be removed from the plants without compromising their viability. Thus, genomic DNA is isolated for further processing to find specific genetic characteristics. In the subsequent processing, these characteristics are linked to traits of interest and are thereby used to predict the presence or absence of the traits of interest in the sampled plants.
As a practical matter, the identification of plants involves complicated procedures that are difficult, if not impossible, to accomplish on-site in the field. The situation becomes further complicated when a large number of plants are involved, such as in a commercial agricultural operation where thousands, or tens of thousands, of different plants are being cultivated in the same field. In such operations, the ability to subsequently identify a particular plant may be of crucial importance. Further, the samples must be easily collected and efficiently presented for processing. Also, whatever device is used to collect the samples of plant material must be capable of reliable operation through many repetitive cycles, for prolonged periods of time. For instance, samples may need to be taken from several thousand different plants. According to the present invention, these samples can be taken from different plant tissue, including but not limited to stem, root, or seed tissue. Preferably, these samples can be taken from the leaves or cotyledons of the plants.
A particularly effective mechanism for collecting samples of plant material is the rather well known punch and die. Such a mechanism, however, is not problem-free. For one, the punch and die must consistently remove samples from the plants without fouling the mechanism. This requires a clean cut of the sample, and an effective separation of the cut sample from the plant. For another, any clogging or contamination of the punch mechanism that might result from the accumulation of solid and liquid debris must be avoided or, at least, minimized. On this last point, it has been determined that the punch clogging phenomenon is highly dependent on the ambient temperature and the relative humidity. Within these parameters, a warm, dry ambient condition has been determined to be most conducive to punch clogging. Tests have shown, however, that this problem can be effectively alleviated by periodically applying water on the punch and die mechanism.
In light of the above, it is an object of the present invention to provide a device for collecting samples of material from plants that consistently cuts and removes samples from a plant for further processing. Another object of the present invention is to achieve sustained operation of a device for collecting samples of material from plants by effectively preventing any clogging of the device by solid and liquid debris. Still another object of the present invention is to provide a device for collecting samples of material from plants that is easy to use, is relatively simple to manufacture, and is comparatively cost effective.